Table 1. List of fish recorded from the Middle Zambezi area (from Jackson, 1961). Some names have been changed in accordance with recent systematic approaches (e.g., Jackson, 1975; Trewavas, 1980; Skelton et al., 1980)
Adults > 18 cm length | Adults < 18 cm length |
Anguilla nebulosa labiata | Alestes imberi |
Protopterus annectens | Micralestes acutidens |
Mormyrus longirostris | Barbus barotseensis1 |
M. deliciosus | B. fasciatus |
Hippopotamyrus discorhynchus | Opsaridium zambezense |
Hydrocynus vittatus | Chiloglanis neumanni |
Distichodus mossambicus | Aplocheilichthys jonhstonii |
D. schenga | Pharyngochromis darlingi |
Labeo altivelis | |
L. congoro | |
Barbus marequensis | |
Eutropius depressirostris | |
Synodontis zambezensis | |
S. nebulosus (?) | |
Clarias gariepinus | |
Heterobranchus longifilis | |
Malapterurus electricus | |
Oreochromis mortimeri | |
Tilapia rendalli | |
Serranochromis codringtoni |
Table 2. Main morphometric features of major African lakes. Data from Welcomme (1982), Balon and Coche (1974), Bernacsek and Lopes (in press), Bowmaker et al. (1978) and Marshall et al. (1982)
Kariba | Cahora Bassa | Nasser/Nubia | Volta | Kainji | Kossou | |
Length (km) | 320 | 246 | 482 | 400 | 137 | 180 |
Width, mean (km) | 19.4 | 10.8 | 13.0 | 6.8 | 9.3 | 8.9 |
Width, maximum (km) | 40 | 40 | 20 | 24 | 24 | |
Depth, mean (m) | 29.2 | 20.9 | 25 | 18.6 | 12.3 | 18.4 |
Depth, maximum (m) | 120 | 156 | 130 | 75 | 50 | 54 |
Shoreline length (km) | 2 164 | 1 775 | 8 804 | 4 828 | 720 | 3 500 |
Shoreline development | 8.3 | 9.7 | 31.2 | 14.5 | 5.7 | 24.7 |
Area (km2) | 5 364 | 2 665 | 6 276 | 8 845 | 1 280 | 1 600 |
Volume (km3) | 156.5 | 55.8 | 158 | 165 | 15.8 | 29.5 |
Approx. outflow: Volume ratio | 1:3 | 2:1 | 1:2 | 1:4 | 4:1 | 1:5 |
Table 3. Average annual water budget for Kariba (1975/76–1979/80). Data from Central African Power Corporation (From Marshall et al., 1982)
km3 | % | |||
Gains: | Rainfall on lake surface | 5.0 | 7.6 | |
Inflows | - Zambezi R. (Livingstone) | 51.7 | 78.4 | |
-Secondary rivers | 9.2 | 14.0 | ||
Total | 65.9 | |||
Losses: | Gross evaporation | 8.6 | 13.2 | |
Outflows | - Turbines | 27.6 | 42.3 | |
- Spillage | 29.0 | 44.5 | ||
Total | 65.2 |
Theoretical Replacement Time (Volume: Inflow) 2.4 yrs
Table 4. The potential fish yield from some African man-made lakes using the MEI relationship (from Marshall, 1982)
MEI | Yield (kg/ha-1yr-1) | |
Volta (Ghana)1 | 6.1 | 32.77 |
Nasser-Nubia (Egypt & Sudan)1 | 9.2 | 40.4 |
Kainji (Nigeria)1 | 6.6 | 34.6 |
Kariba (Zimbabwe & Zambia)2 | 2.8 | 23.2 |
Mwenje (Zimbabwe)3 | 10.0 | 42.1 |
Darwendale (Zimbabwe)4 | 16.8 | 53.6 |
McIlwaine (Zimbabwe)3 | 17.1 | 54.1 |
Claw (Zimbabwe)4 | 17.2 | 54.2 |
Mazoe (Zimbabwe)3 | 34.6 | 75.2 |
Sources: 1 Henderson and Welcomme (1974)
2 Marshall et al. (1982)
3 Mitchell and Marshall (1975)
4 Thornton (1980)
Table 5. Average ionic composition of Lake Kariba surface water compared to average African and World fresh waters (from Coche, 1974)
Ion | Lake Kariba 1965 average | World fresh waters average | African fresh water average | East and West African lakes and rivers | |||||
meq.L-1 | % | meq.L-1 | % | meq.L-1 | mg.L-1 | meq.L-1 | % | mg.L-1 | |
Calcium | 0.465 | 57 | 1.49 | 64 | 0.624 | 12.5 | 0.324 | 29 | 6.5 |
Magnesium | 0.160 | 20 | 0.42 | 17 | 0.313 | 3.8 | 0.239 | 21 | 2.9 |
Sodium | 0.153 | 18 | 0.36 | 16 | 0.479 | 11.0 | 0.392 | 34 | 9.0 |
Potassium | 0.042 | 5 | 0.08 | 3 | ? | ? | 0.182 | 16 | 7.1 |
Total cations | 0.820 | 100 | 2.35 | 100 | - | - | 1.137 | 100 | 25.5 |
Fixed CO2 | 0.756 | 89 | 1.71 | 74 | ? | ? | (0.725) | (64) | (21.8) |
SO4 | (0.062) | (7) | 0.37 | 16 | 0.281 | 13.5 | 0.229 | (20) | 11.0 |
Cl | (0.028) | (3) | 0.23 | 10 | 0.341 | 12.1 | 0.183 | (16) | 6.5 |
Salinity | 1.67 | - | 4.66 | - | (4.5) | - | (2.27) | (100) | (39.3) |
SiO2 | 12.3 mg/L | 17.1 mg/L | - | 23.2 | - | - | 15.5 | ||
Reference | Pers.data | Gorham, 1957 | Livingstone, 1963 | Visser cited in Imevbore, 1970 |
Table 7. Provisional chemical budget for Lake Kariba.
(From Coche, 1974)
t × 1 000 | |||
Imports | - Zambezi River | 1 695 | |
- Secondary Rivers | 419 | ||
- Rainfall | 42 | ||
TOTAL | 2 156 | ||
Exports | - outflow | 2 346 |
Table 6. Water quality of some African rivers, major inflows for lakes and rservoirs (from Coche, 1974)
River | Range temp. °C | Spec. cond. at 20°C micromhos | Salinity mg L-1 | Cations, mg L-1 | Anions, mg L-1 | ||||||
Ca | Mg | Na | K | HCO2+CO3 | Cl | SO4 | |||||
Zambezi (L. Kariba) | 17–30 | 36–121 | 20–70 | 4.7–16.9 | 0.9– 7.3 | 1–8 | 0–2 | 12–36 | (3) | (3) | Original data |
Blue Nile (Khartoum) | - | 140–390 | - | 19.6–28.1 | 5.0– 6.5 | 4.5–9.0 | 1.7–2.9 | 49–80 | 2.0–7.3 | - | Hammerton, 1972 |
White Nile (Khartoum) | - | 220–500 | - | 14.2–19.0 | 7.5–11.7 | 25–41 | 6.9–9.2 | 69–99 | 6.0–9.5 | - | |
Nile (L. Nubia) | 17–28 | (190) | - | 25 | 7 | 17 | 4 | 134 | 4.5 | 9 | Entz (pers.comm.) |
Niger (L. Kainji) | (25–30) | 34–80 | - | 4.11 | 2.60 | 3.49 | 2.41 | 12–19 | 1.36 | T | Imevbore, 1970 |
Volta (Ajena, L. Volta) | (25–30) | (60) | - | 6.67 | 2.9 | (2.4–3.5) | (1.4–2.6) | 40.3 | 4.6 | 12.7 | Entz, 1969 (Biswas, 1968) |
Bandama (L. Kossou) | (25–29) | 90–200 | - | 4.4–5.0 | - | 5.8–6.4 | 1.6–2.5 | 24–36 | 1–3.5 | 0.2–1.0 | CTFT, 1972 Welcomme, 1972 |
Kafue (Flood Plain) | 15–32 | 135–350 | Avg. 202 | 18–102 | 7–57 | 1.7–15 | 0.8–4 | 25–114 | 1.6–10 | (T) | Tait, 1967 |
Luapula (L. Mweru) | 21–27 | 44–108 | 32–72 | 4.3–12.8 | 1.8–8.6 | 3.7–6.2 | 0.6–1.7 | 15–38 | 1.8–5.8 | 1–3 | De Kimpe, 1964 Symoens, 1968 |
Congo (Matadi, April 1966) | - | 40 | 30.7 | 2.71 | 1.81 | 3.15 | 1.72 | 9.46 | 6.48 | 5.32 | Symoens, 1968 |
Table 8. Fish species of Lake Kariba, Middle Zambezi and possible invaders from Upper Zambezi. (Data from Jackson, 1961; Jubb, 1961 and 1967; Bell-Cross, 1972; Balon, 1974)
Present before Kariba | Present in Lake Kariba | Widespread in Middle Zambezi | Introduced | Possible Upper Zambezi invader | |
Protopterus annectens (1) | X | ||||
Anguilla nebulosa labiata | X | X | X | ||
Limnothrissa miodon | X | X | |||
Mormyrops deliciosus | X | X | X | ||
Hyppopotamyrus discorhynchus | X | X | |||
Marcusenius macrolepidotus | X | X | |||
Mormyrus longirostris | X | X | X | ||
Hydrocynus vittatus | X | X | X | ||
Alestes lateralis (2) | X | X | |||
A. imberi | X | X | X | ||
Micralestes acutidens | X | X | X | ||
Distichodus mossambicus | X | X | |||
D. schenga | X | X | |||
Barbus poechii (3) | X | ||||
B. paludinosus | X | X | |||
B. unitaeniatus | X | X | |||
B. lineomaculatus | X | X | |||
B. barotseensis (4) | X | X | |||
B. fasciolatus | X | X | |||
B. marequensis | X | X | X | ||
B. radiatus | X | X | |||
Labeo cylindricus | X | X | |||
L. congoro | X | X | |||
L. altivelis | X | X | X | ||
Opsaridium zambezense | X | ? | X | X | |
Chiloglanis neumani (5) | X | ||||
Schilbe mystus (6) | X | X | |||
Eutropius depressirostris | X | X | |||
Clarias gariepinus | X | X | X | ||
Heterobranchus longifilis | X | X | |||
Malapterurus electricus | X | X | |||
Synodontis zambezensis | X | X | |||
S. nebulosus | X | X | |||
Aplocheilichthys johnstoni | X | X | |||
Serranochromis codringtoni | X | X | |||
S. giardi | X | ? | X | ||
S. carlottae | X | ? | X | ||
S. macrocephalus (7) | X | ? | X | ||
S. robustus (8) | X | X | X | ||
Pharyngochromis darlingi | X | X | X | ||
Pseudocrenilabrus philander | X | X | |||
Oreochromis andersoni | X | ? | X | ||
O. macrochir | X | X | X | ||
O. mortimeri | X | X | |||
Tilapia rendalli | X | X | X | X |
(1) Inhabits temporary pools, habitat destroyed
(2) Jubb (1976) claims that it was recorded from Middle Zambezi also that it may not be A. lateralis
(3) Found in N. Bank tributaries above and below Kariba (Balon, 1974, 1974a)
(4) Possibly misidentified. Occurs, however, in Kalomo River above Kariba (Balon, 1974)
(5) Inhabits running water, habitat destroyed
(6) Recorded from Middle Zambezi before Kariba (Jubb, 1967)
(7) Found in Chezia R., N. Bank tributary (J.F.R.O, 1967)
(8) Found in N. Bank tributaries (J.F.R.O, 1961; Balon, 1974) Also introduced (Toots and Bowmaker, 1976)
Table 9. Fish abundance in relation to vegetation
Habitat type | Species | No. ha-1 | kg ha-1 | Source |
Gentle slope, rich vegetation | 14 | 20 200 | 500 | (1) |
Intermediate slope, poor vegetation | 12 | 7 700 | 132 | |
Steep and rocky, very poor vegetation | 11 | 1 100 | 48 | |
Intermediate slope, no vegetation, (9–12 m deep) | 6 | 1 800 | 27 | |
Open water, 20 m deep | 3 | 300 | 9 | |
Permanent Salvinia mat | 25 | 816 | (2) | |
Rooted hydrophytes present | 24 | 263 | ||
Poor vegetation | 20 | 98 | ||
Good vegetation in coves (5 stations) | 23 | 43 283 | (3) | |
Poor vegetation in coves (3 stations) | 17 | 1 988 |
Sources: (1) J.D. Langerman, Unpubl. (1981–82 data)
(2) Mitchell (1976)
(3) Balon (1973)
Table 10. Changes in the abundance of major fish species, lakeside station 1960–1982. Expressed as numbers per 50 standard gillnet fleet settings
1960 | 1961 | 1962 | 1963 | 1964 | 1965 | 1966 | 1967 | 1968 | 1969 | 1970 | |
Hyppopotamyrus discorhynchus | - | - | - | - | 13 | N.D. | N.D. | 20 | N.D. | 225 | 318 |
Mormyrus longirostris | - | - | 5 | - | 4 | - | - | 24 | |||
Mormyrops deliciosus | - | - | - | - | 32 | - | - | 6 | |||
Marcusenius macrolepidotus | - | - | - | - | - | 90 | 602 | 294 | |||
Hydrocynus vittatus | 2 900 | 2 000 | 2 773 | 3 258 | 2 058 | 1 370 | 2 876 | 2 718 | |||
Alestes imberi | 3 150 | 2 200 | 968 | 1 233 | 180 | 110 | - | 6 | |||
Labeo congoro | 850 | 900 | 614 | 563 | 179 | - | 4 | - | |||
L. altivelis | 10 800 | 3 700 | 1 482 | 821 | 477 | - | - | - | |||
Eutropius depressirostris | - | - | 46 | 146 | 18 | 80 | 664 | 900 | |||
Synodontis zambezensis | - | - | - | - | 26 | - | 63 | 18 | |||
Clarias gariepinus | 600 | 1 450 | 828 | 667 | 45 | 90 | 209 | 42 | |||
Heterobranchus longifilis | - | - | - | - | - | - | - | 6 | |||
Distichodus schenga | 150 | 200 | 109 | 46 | 75 | 50 | 5 | 6 | |||
D. mossambicus | 250 | 450 | 1 775 | 63 | 39 | - | - | - | |||
Tilapia rendalli | - | 150 | 23 | 46 | 9 | 40 | 83 | 18 | |||
Serranochromis codringtoni | - | 1 | 50 | 21 | 6 | 140 | 401 | 162 | |||
Oreochromis mortimeri | 1 900 | 50 | 1 050 | 408 | 139 | 480 | 915 | 192 | |||
O. macrochir | - | - | - | - | - | - | - | - |
1971 | 1972 | 1973 | 1974 | 1975 | 1976 | 1977 | 19781 | 19791 | 1980 | 1981 | 19822 | |
Hyppopotamyrus discorhyncus | 556 | 1 090 | 1 028 | 532 | 159 | 378 | 389 | 500 | 286 | 565 | N.D. | 270 |
Mormyrus longirostris | 16 | 68 | 141 | 277 | 413 | 460 | 443 | 159 | 91 | 122 | 284 | |
Mormyrops deliciosus | - | - | - | 20 | 6 | 11 | 7 | 9 | 8 | 18 | 26 | |
Marcusenius macrolepidotus | 800 | 371 | 324 | 266 | 68 | 96 | 165 | 275 | 112 | 184 | 33 | |
Hydrocynus vittatus | 5 936 | 6 042 | 4 466 | 7 020 | 4 219 | 2 906 | 1 979 | 1 808 | 1 332 | 1 646 | 2 095 | |
Alestes imberi | 36 | 50 | 30 | 206 | 994 | 1 093 | 1 379 | 827 | 1 649 | 1 364 | 878 | |
Labeo congoro | - | - | 2 | 2 | - | 1 | 1 | 1 | - | - | - | |
L. altivelis | - | 6 | 4 | 2 | 22 | 8 | 44 | 28 | 90 | 87 | 18 | |
Eutropius depressirostris | 1 260 | 694 | 295 | 604 | 212 | 160 | 601 | 299 | 324 | 735 | 162 | |
Synodontis zambezensis | 36 | 50 | 99 | 167 | 88 | 103 | 125 | 80 | 57 | 103 | 84 | |
Clarias gariepinus | 48 | 172 | 104 | 458 | 345 | 231 | 168 | 294 | 73 | 78 | 204 | |
Heterobranchus longifilis | - | 3 | 4 | 6 | 12 | 13 | 16 | 2 | 1 | 2 | 4 | |
Distichodus schenga | - | 6 | 6 | 12 | 2 | 4 | 1 | 4 | 1 | - | 1 | |
D. mossambicus | - | - | - | - | - | - | - | - | - | - | 1 | |
Tilapia rendalli | 80 | 141 | 64 | 193 | 304 | 314 | 144 | 132 | 248 | 80 | 117 | |
Serranochromis codringtoni | 312 | 1 635 | 1 145 | 1 967 | 2 439 | 1 860 | 1 118 | 723 | 571 | 534 | 1 567 | |
Oreochromis mortimeri | 356 | 1 039 | 757 | 2 682 | 2 032 | 1 613 | 1 481 | 1 173 | 135 | 170 | 328 | |
O. macrochir | - | - | - | 2 | 16 | 19 | 12 | 5 | 15 | 1 | 4 |
1 Some commercial fishing took place from 1978 to mid-1980
Table 11. Standing stock of major fish species (i.e., > 1% of total standing stock) in Lake Kariba
Balon (1973) | Mitchell (1976) | Langerman (unpubl.) | ||||
kg ha-1 | % | kg ha-1 | % | kg ha-1 | % | |
Mormyrops deliciosus | 92 | 15.1 | 126 | 30.0 | ||
Hippopotamyrus discorhyncus | 96 | 15.9 | 70 | 16.7 | ||
Marcusenius macrolepidotus | 8 | 1.8 | ||||
Mormyrus longirostris | 18 | 3.0 | 45 | 10.6 | ||
Hydrocynus vittatus | 31 | 5.1 | 10 | 2.5 | 64 | 15.3 |
Alestes lateralis | 29 | 4.8 | 6 | 1.4 | 13 | 3.1 |
A. imberi | 13 | 3.0 | ||||
Labeo altivelis | 6 | 1.0 | 53 | 12.6 | ||
Eutropius depressirostris | 9 | 1.5 | ||||
Clarias gariepinus | 52 | 8.6 | 13 | 3.2 | ||
Heterobranchus longifilis | 14 | 2.3 | 7 | 1.7 | ||
Malapterurus electricus | 48 | 8.0 | 10 | 2.3 | 5 | 1.3 |
Serranochromis codringtoni | 13 | 2.2 | 12 | 2.9 | 33 | 8.0 |
S. macrocephalus | 12 | 2.9 | ||||
Pharyngochromis darlingi | 1.1 | |||||
Oreochromis mortimeri | 97 | 16.0 | 22 | 5.2 | 25 | 6.1 |
Tilapia rendalli | 56 | 9.3 | 54 | 12.7 | 190 | 45,3 |
TOTAL | 580 | 96.0 | 409 | 97.2 | 408 | 97.6 |
Sampling period | 1968–1971 | 1972–1974 | 1981–1982 |